In various industries, items are sold in batches satisfying various constraints. As an example, items of non-uniform size, shape or weight, e.g. food items such as meat, fish, fruit and vegetables, are typically handled and delivered to customers in batches having a substantially uniform size, shape and weight. Typically, a batch of items must fulfill requirements defined by a contract between a delivering and a receiving part, and most often, minimum weight of the batch is a key issue. Normally, the part of the batch that exceeds the minimum weight is considered by the delivering part as a loss and is often referred to as “giveaway”, “overweight” or “overpack”.
Typically, batches are formed by weighing the items individually, e.g. as they are moved by a conveyer system across a dynamic scale. In a computer system, the weight of each item is compared with weights of a plurality of receptacles, e.g. bins wherein batches are formed. Often, the computer system uses statistical algorithms for assigning specific items to specific bins under consideration of required minimum weight of the batch and a desire not to produce batches with more overweight, i.e. giveaway, than required under the present conditions, i.e. given the weights of the items and the required minimum weight of the batches.
Evidently, there is a correlation between the amount of giveaway, the required minimum weight of the batches, and the weight distribution of the items being batched. In general, the larger the items are and the smaller the batches are, the more giveaway is expected.
Existing systems for batching items, e.g. conveyor systems for continuous batching of food items, are sometimes provided with a computer system, which is capable of registering certain process parameters, e.g. the batching throughput, e.g. determined in weight units or determined in numbers of pieces per time unit. It is, however, very difficult even for skilled operators to evaluate the performance of the system. As an example, an operator may be satisfied by knowing that a large number of batches are formed within a certain time unit, while he never realizes that the amount of giveaway or the amount of batches with underweight is large, and even if control weighing of the batches reveals the truth, the complex nature of the batching process makes it difficult to determine the reason for the large number of batches with overweight or underweight, neither to say if the situation is better or worse than expected. One reason for an undesirable result could be that the weight distribution of the items is not suitable for the batch or pack size being processed and another reason could be that a scale is out of order. In the existing systems for batching, it is therefore difficult to optimize the batching process, e.g. with the objective to minimize giveaway.